cell membrane

Cholesterol restricts the lateral movement of phospholipids, thus decreasing fluidity at high temperatures.

Transmembrane pumps (like the Na+/K+ pump) use ATP to change conformation and transport ions.

They hypothesized that the lipid bilayer was coated on both sides by globular proteins.

Receptors are usually transmembrane integral proteins that span the membrane to receive signals.

Osmosis is defined as the net movement of water across a membrane driven by a water potential gradient.

Channel proteins provide a physical pathway, whereas carrier proteins undergo conformational changes to transport substances.

In hypertonic environments, the external water potential is lower than the cell, causing water to exit by osmosis.

The membrane is fluid and dynamic, not rigid or crystalline.

By measuring the surface area of extracted lipids, they determined it was twice the surface area of the RBC.

The phospholipid bilayer provides the fundamental hydrophobic barrier essential for cellular compartmentalization.

The two hydrocarbon chains (fatty acids) are non-polar and hydrophobic.

Facilitated diffusion requires either channel or carrier proteins to assist polar molecules.

Passive transport relies on kinetic energy (gradient), while active transport requires metabolic energy (ATP).

Carbohydrate chains are attached to proteins/lipids only on the non-cytosolic side of the membrane.

Cell wall thickness is unrelated to the fluidity of the plasma membrane.

Glycoproteins and glycolipids act as cellular "identity tags" and mediate cell-cell adhesion.

Transmembrane proteins are a subset of integral proteins that traverse both leaflets of the bilayer.

The mosaic aspect describes the heterogeneous arrangement of proteins scattered throughout the phospholipid bilayer.

The hydrophobic core of the phospholipid bilayer prevents the free passage of polar/charged molecules.